One model I purchased was a Forgeworld Ork KilKannon. I am intending to use it with my new Ork vehicles.
This is the weapon on an Ork Halftrakk as seen at GamesDay 2009.
The resin parts are as seen here.
You get three Grot Krew and a case of shells. One of the key things you need to do with virtually all Forge World models is to give them a good wash.
When the Forge World models are cast, the mould is given a spray (I guess) of some kind of lubricant to allow the cast model to be released from the mould easily. However the lubricant also acts as a barrier to paint, so as happened with previous models I (and others) have painted is that the paint flecks off.
Washing the model in water with a drop of washing up liquid should remove the lubricant. Avoid using hot water as this could warp the resin (a useful tip if you need to bend warped resin back to its original shape).
The model goes together really easily.
See the workbench feature on the Forgeworld Ork KilKannon.